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Title: Miscibility Gap Closure, Interface Morphology, and Phase Microstructure of 3D LixFePO 4 Nanoparticles from Surface Wetting and Coherency Strain

We study the mesoscopic effects which suppress phase-segregation in LixFePO4 nanoparticles using a multiphysics phase-field model implement on a high performance cluster. We simulate 3D spherical particles of radii from 3nm to 40nm and examine the equilibrium microstructure and voltage profiles as a they depend on size and overall lithiation. The model includes anisotropic, concentration-dependent elastic moduli, misfit strain, and facet dependent surface wetting within a Cahn-Hilliard formulation. Here, we find that the miscibility gap vanishes for particles of radius ~ 5 nm, and the solubility limits change with overall particle lithiation. The corresponding voltage plateau, indicative of phase-segregation, changes in extent and also vanishes. Surface wetting is found to have a strong effect on stabilizing a variety of microstructures, exaggerating the shifting of solubility limits, and shortening the voltage plateau.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Univ. of Chicago, IL (United States). Computation Inst.
  3. Northwestern Univ., Evanston, IL (United States). McCormick School of Engineering
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Univ. of Chicago, IL (United States). Computation Inst.
Publication Date:
OSTI Identifier:
1237941
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 9; Journal Issue: 10; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Department of Commerce
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY Li-ion battery; LiFePO4; coherency strain; interface morphology; nanoparticles; phase-field model; surface wetting